1. Field of the Invention
The invention relates to a bonding contact area on a semiconductor substrate with a reinforcing structure.
2. Description of the Background Art
Bonding contact areas usually have a layer sequence of dielectrics, as well as contact and metallization levels. The top layer, called the bonding surface (bonding pad), is connected electrically by so-called bonding with a thin wire in the “package.”
It is known that during a bonding process, mechanical loading and ultrasonic stresses applied by the bonding capillary tip to the bonding contact area can lead to a fracture up to breaking of the underlying dielectrics, deformation of the underlying metal structures, and delamination of the layers in the metal structures. These bonding failures may appear as craters in the bonding contact area and underlying layers and are usually not apparent during bonding but manifest themselves only during subsequent pull and shear tests or reliability tests.
These problems intensify as a result of new process options, such as 3-layer metallization, chip planarization (chemical-mechanical planarization), and replacement of gold bond wires by copper bond wires.
Thus, it is known to provide bonding contact areas with reinforcing structures uniformly or periodically in the lateral direction to improve their mechanical properties.
EP 0 875 934 B1, which corresponds to U.S. U.S. Pat. No. 6,143,396, describes a bonding contact area with at least one dielectric layer, which has a patterned reinforcing structure, which consists of interconnected metallization lines, arranged in a grid, for example.